The current guidelines recommend endoscopic treatment of asymptomatic bile duct stones with ERCP. However, the natural history of asymptomatic bile duct stones remains unclear, and the appropriateness of aggressive endoscopic treatment of asymptomatic bile duct stones remains to be discussed. The risk of ERCP-related complications, especially post-ERCP pancreatitis, may be higher in asymptomatic patients with bile duct stones than in symptomatic patients. There is no prospective study to investigate whether ERCP is better than wait-and-see in asymptomatic patients with bile duct stones, and the risk of inducing ERCP-related complications cannot be balanced against the risk of complications in patients who are followed without treatment. To clarify the justification for aggressive treatment of asymptomatic bile duct stones, large-scale, multicenter studies should be conducted to evaluate the long-term risk of complications in the ERCP and wait-and-see groups.

Self-expandable metallic stents (SEMS) with longer patency have been recommended for endoscopic drainage of unresectable malignant biliary obstruction. Recently developed chemotherapy regimens have prolonged the survival of patients with malignant pancreatobiliary disease. As a result, we have increasingly encountered patients requiring re-intervention for recurrent biliary obstruction (RBO) due to SEMS dysfunction. These patients are often in poor general condition which can quickly worsen without appropriate interventions. Therefore, such patients require prompt and appropriate therapeutic management. For re-intervention, we should develop a treatment strategy for RBO that considers the primary disease, approach, location and form of SEMS placement, and type of SEMS. The clinical state is often complicated, involving a variety of factors. Hence, a multidisciplinary treatment protocol must be employed, in collaboration with surgeons and radiologists, rather than adhering to endoscopic therapy alone.

Pancreaticobiliary maljunction is a congenital malformation in which the pancreatic and bile ducts join anatomically outside the duodenal wall. This malformation is classified into a dilated bile duct type (congenital biliary dilatation) and a non-dilated bile duct type. Pancreaticobiliary maljunction causes pancreatic juice to reflux into the bile duct, causing inflammation, duct dilatation, and the possibility of malignant transformation; therefore, surgery is indicated. Surgical management for congenital biliary dilatation comprises bile duct resection with cholecystectomy followed by biliary reconstruction, and the management for the non-dilated type of pancreaticobiliary maljunction is prophylactic cholecystectomy. Insurance reimbursements have covered laparoscopic surgery for congenital biliary dilatation since 2016 and robot-assisted surgery since 2022 in Japan. Careful long-term postoperative follow-up in both diseases is necessary to identify cholangiocarcinogenesis of the remnant bile duct.

A 54-year-old man was referred to our hospital for an enlarged duodenal papilla detected by a routine upper gastrointestinal endoscopy. Endoscopic ultrasonography revealed a 10-mm round shape hypoechoic tumor in the submucosal layer without intraductal extension. An endoscopic biopsy showed suspicion of neuroendocrine tumor. The patient was asymptomatic without hypertension, and blood tests showed catecholamine 3 fractions in the normal range. Contrast-enhanced CT scan did not reveal any duodenal involvement, significant lymph node enlargement, or distant metastasis. Endoscopic papillotomy was performed, and the patient was discharged on postoperative day 5 with good progress. Based on the histological and immunostaining findings, the tumor was diagnosed as a gangliocytic paraganglioma.

A 75-year-old man with unresectable locally advanced pancreatic body cancer underwent chemotherapy after biliary drainage with uncoverd self-expandable metal stent (SEMS). The patient was referred to our department due to hematemesis. Upper gastrointestinal endoscopy could not find out a bleeding point. Contrast-enhanced CT showed no aneurysm, but a suspicious finding of extensive blood clots from the right hepatic duct to the common bile duct. Because laboratory data showed jaundice with inflammation suspected of cholangitis, emergency ERCP was intended for biliary drainage. However, when ERCP was performed, we saw a large amount of fresh blood was overflowing from the bile duct, then we decided to use a stone retrieval balloon to identify the bleeding point. After repeated dilatation while moving the balloon from the distal common bile duct to the both hepatic ducts, the bleeding from the bile duct stopped even after dilatation in the right hepatic duct, and we assumed that the bleeding was coming from the same area. A fully-covered SEMS was placed from the common bile duct to the right anterior segment branch, and the bleeding was continuously stopped. This procedure is a useful novel method to detect bleeding point of hemobilia.

A 75-year-old woman had received 2 months of chemotherapy with gemcitabine and nab-paclitaxel for pancreatic ductal carcinoma. During the treatment, she presented with abdominal pain and elevated liver enzymes. Even after the chemotherapy was discontinued, the symptoms continued and she was admitted. ERC revealed dilatation of the bile duct and no biliary obstruction. Changes like shaggy appearance were visible at bile duct wall. She was diagnosed as an eosinophilic cholangitis based on eosinophil infiltration in the biliary duct wall of the biopsy sample. The liver enzymes and abdominal symptoms were normalized after the administration of an oral steroid. After the normalization, She showed no major side effects during the chemotherapy with gemcitabine monotherapy. These results raised a suspicion of eosinophilic cholangitis caused by chemotherapy with nab-paclitaxel. To the best of our knowledge, there few reports of eosinophilic cholangitis caused by chemotherapy with nab-paclitaxel. We report with literature review discussion.

The patient was a female in her 80s who had received laparoscopic cholecystectomy due to a gallstone 8 years previously. She had pain from the right precordial region to the back. Dynamic CT of the abdomen showed dilatation of the intra- and extrahepatic bile duct and a tumor of 3.5×2 cm with contrast enhancement that filled the lumens of the dilated remnant cystic duct to the common hepatic duct and intrapancreatic bile duct. MRCP delineated the remnant cystic duct as a defect due to a tumor of 4 cm in diameter showing papillary growth, and the tumor extended into the common bile duct. No extrabiliary infiltration was noted, and subtotal stomach-preserving pancreaticoduodenectomy was performed with a diagnosis of primary papillary tumor of the remnant cystic duct. On gross examination of the excised specimen, the lesion was a papillary tumor of 3.4×2.2 cm having the base in the remnant cystic duct with no mucus in the bile duct. Histopathological examination characterized the lesion as a carcinoma in situ, and a diagnosis of intracholecystic papillary neoplasm with high-grade intraepithelial neoplasia was made. Although no grossly elevated lesion was detected from the common hepatic duct to common bile duct, moderate atypia corresponding to low-grade BilIN was histologically demonstrated.

Drug therapy for biliary tract cancer has long been developed mainly with cytotoxic agents, and its effectiveness has been evaluated each biliary site together. However, the differences in clinical conditions and genetic alterations for each biliary sites have been clarified. Biliary tract cancer is also characterized by many genetic alterations that can be target for molecular-targeted agents. Therefore, there are high expectations for precision medicine based on genetic alterations for the treatment of biliary tract cancer. Several effectiveness of molecular-targeted agents and immunotherapy based on genetic alterations have been reported so far. In recent years, gene panel tests have become widespread in Japan, and precision medicine based on gene alterations identified from comprehensive genomic profiling has become possible in daily clinical practice. On the other hand, there are many issues to be solved, such as the system for providing matched therapeutic drugs for the patients, the difficulty of collecting enough tissues for comprehensive genomic profiling, and the problem of acquisition resistance due to the use of molecular-target drugs. Therefore, further development is needed to solve these problems in the future.